1. Field of the Invention
The present invention relates an inorganic/organic complex of clay and polyoxyalkylene amine and a method for producing the same, the complex in which can be particularly applied to oily surfactants and reinforcing agents of polymers.
2. Description of the Related Technology
Currently, inorganic/organic polymer composite materials under a nanoscale regime are one of the most significant materials, and thus have been widely investigated and developed. Such composite materials are dual-phased wherein at least one phase is dispersed under a nanoscale regime. Accordingly, compatibility between the two phases, for example, clay and polymers, is always essential for the nanoscale dispersion.
For layered silicate clay which is hydrophilic and immiscible with most organic solvents, the interlayer distances can be enlarged by means of intercalating with organic quaternary ammonium, and thus monomers are allowed to enter therethrough. The monomers can be polymerized to obtain an exfoliated inorganic/organic polymer composite material. In principle, the distances, enlarged by intercalating agents, are constant and required to be wide enough for monomer or polymer molecules to enter. As for exfoliation, the interlayer distances are irregular and different directions may occur in each layer.
Conventional intercalating agents such as 12-aminolauric acid, hexadecylamine, fatty amine, bis(2-hydroxyethyl) methyl tallow alkyl ammonium chloride and stearylamine, usually have low molecular weights, and interlayer distances of the clay can be expanded to a certain degree.
Referring to the research of T. J. Pinnavaia (Michigan State University), intercalating agent CH3(CH2)nxe2x80x94NH3+ is provided to mixed with montmorillonite (MMT), which is then dispersed in diglycidyl ether of BPA (epoxy resin Epon828) to form a polyether-clay composite material under a nanoscale regime. For such intercalating agent, the interlayer distances can be enlarged to 18.0 xc3x85. The epoxy resin can then form an epoxy/clay material through self polymerization at 75xc2x0 C. This reference also indicates an improvement in heat distortion temperature. The intercalating agent performs a rule of monolayer to bilayer, and even to pseudo-trimolayer. The interlayer distance ranges between 13.8-18.0 xc3x85, which allow the epoxy resin to enter and polymerize therein, and further to exfoliate the layered inorganic matter so that application effect of nonomaterials can be achieved.
Japanese Patent No. 8-22946 discloses the first commercial inorganic/organic polymer composite material under a nanoscale regime, which is developed by Toyota company. This composite material is produced by dispersing [H3N+(CH2)11COOxe2x88x92]-montmorillonite in Nylon 6, wherein the aminocarboxylic acid is provided as an intercalating agent and the polymers are formed between layers of the clay through condensation of caprolactam monomers. However, the aminocarboxylic acid doesn""t facilitate nonpolar polymers such as polyethylene and polypropylene, to uniformly disperse in the hydrophilic layered silicate. Accordingly, Japanese Patent Publication No. 8-53572 provides organic onium ions as an intercalating agent to mix with layered silicate, which can be uniformly dispersed in molten polyolefin resin. Unfortunately, though the organic onium ions can enlarge the interlayer distances, affinity between the intercalating agent and the polyolefin resin is not enough to exfoliate the layered silicate. Further, Japanese Patent Publication No. 10-182892 indicates that when blending in a molten mixture containing olefin oligomers with H-bond and polyolefin resin, the organized layered silicate might be indefinitely swelled due to the strong affinity therebetween. However, it""s a dilemma whether to increase the oligomers for better dispersing or to decrease the oligomers for better mechanical characteristics.
Accordingly, there is a need to ameliorate the composites by means of providing appropriate intercalating agents which could render the intercalated silicates with a wider interlayer distance. Furthermore, the widely opened silicates can be used as novel inorganic/organic surfactants, an important industrial application but deviated from the common nanocomposite usage.
The object of the present invention is to provide a compolex of clay and polyoxyalkylene amine and a method for producing the same, so that the complex is stable enough and has excellent affinity for polymers and organic matters.
In order to achieve the above object, the complex of the present invention primarily includes polyoxyalkylene amine having molecular weight over 1,800 as an intercalating agent and inorganic layered silicate clay.
The polyoxyalkylene amine aforementioned can be polyoxyalkylene diamine, and preferably polyoxypropylene diamine. The commercial product includes Jeffamine series having structure as the following scheme, for example, D-2000 (poly(propyleneglycol) bis (2-aminopropyl ether)), D-4000 (poly(propylene glycol) bis (2-aminopropyl ether)), etc. Additionally, T-3000 (tri-functional poly(propyleneglycol) 2-aminopropyl ether), T-5000 (tri-functional poly(propylene glycol) 2-aminopropyl ether), etc., can be applied, too. 
X=2-3 (Approx. m.w.=230; Jeffamine(copyright) D-230)
X=5-6 (Approx. m.w.=400; Jeffamine(copyright) D-400)
X=33 (Approx. m.w.=2000; Jeffamine(copyright) D-2000)
X=68 (Approx. m.w.=4000; Jeffamine(copyright) D-4000)
The layered silicate clay used in the present invention is not restricted, and preferably montmorillonite, kaolin, mica or talc. In general, the clay with CEC (cation exchange capacity) ranging between 50-200 meq/100 g is preferred.
The method for producing the complex of the present invention is primarily to acidify the polyoxyalkylene amine with an inorganic acid, which is then mixed with the clay swelled with water previously, and then the mixture is powerfully stirred at 60-80xc2x0 C. for cation exchanging to obtain the inorganic/organic complex.
In the above method, xe2x80x94NH2/H+for acidifying the polyoxyalkylene amine is preferably at 2/1 in mole, i.e., a half of the polyoxyalkylene amine is acidified to form a bilayer status. The polyoxyalkylene amine is preferably added at least equal to cation exchange equivalence of the layered inorganic silicate clay, so that enough energy can be supplied to expand interspace of the clay. The inorganic acid is also not restricted, and preferably chloric acid, sulfuric acid, phosphoric acid or nitric acid.
According to the present invention, the complex of clay and polyoxyalkylene amine is hydrophobic, rather than hydrophilic as before the intercalation, and compatible with polymers. The interlayer distances can be enlarged to 48-92 xc3x85, so that polymers are easily further dispersed therein under a nanoscale regime to form inorganic/polymer composite material. The complex can be applied as an oily surfactant and be used to improve characteristics of polymers.